2.42-inch Waveshare OLED SSD1309 and contrast problem

[JG24]

Hi there! Thanks a lot for your work. I managed to get the 2.42-inch Waveshare OLED display up and running. Everything would be fine if it weren't for the lack of ability to adjust the contrast of this display. According to the manufacturer, the display supports contrast control. Unfortunately, I can't seem to achieve it. Has anyone had a similar issue?

Additionally, I'll mention that I have the display connected via SPI to an ESP32.

Here's datasheet: https://files.waveshare.com/wiki/2.42inch-OLED-Module/SSD1309Datasheet.pdf

[olikraus]

which exact constructor did you use?

[JG24]

which exact constructor did you use?

U8G2_SSD1309_128X64_NONAME0_F_4W_HW_SPI u8g2(U8G2_R0, /* cs=/13, / dc=/16, / reset=*/17);

It works very well, except for the ability to change the contrast.

[olikraus]

I checked the code, but the setContrast() command should work.
You can also use

u8g2.sendF("ca", 0x81, contrast); // 'contrast' is the desired contrast value

to manually set the contrast (see also https://github.com/olikraus/u8g2/wiki/u8g2reference#sendf)

Sometimes the contrast command for the display (0x81) does not have the desired effect. In such cases could play around with the 0xd9 or 0xdb command of your display.

[olikraus]

See also here: #1504